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how much water for my tomatoes

Ray 3Ray 3 Posts: 26

Just put my toms in growbags with grow pots and was wondering how much water do they need.The outer rim for watering holds approx 4 pints which I half filled upon finishing  the transplanting and an hour later not much water seems to have gone through to the bags.Does it normally take a good while for water to penetrate  to the bag or is it blocked somehow.I have two plants in each growbag by the way.The plants are approx 12 to 15 inches high with the first flowers just forming..Would half filling every second day be enough.The growbags are in a polytunnel by the way.

Sorry for all the questions but I am new to tomato growing and all replies gratefully appreciated.


  • DovefromaboveDovefromabove Posts: 87,000

    I only water when the soil is dry and the foliage is starting to flag.  

    Overwatering causes the perfect conditions for fungal growth and blight. 

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • PalaisglidePalaisglide Posts: 3,414

    Ray, if the compost in the actual grow bag is very wet then the water in the trays will not feed down, if they are the ones I am thinking the water will only release when the compost dries enough to let air into the container releasing the water.

    I do not use grow bags now only twelve inch pots which can be topped up with fresh compost every few weeks. Using a large coke bottle with a hole drilled in the cap, filled with water then upended into the compost works on the air release system thus feeding water into the pot when required. When I did use grow bags cutting slits along the side stopped them from getting water logged as the spare water leaked out. as Dove says over watering is not good although I would not let them flag either. One way is to dip a finger in the compost if it comes out muddy too wet, if it comes out clean too dry it should have some compost sticking to the finger just right.


  • WelshonionWelshonion Posts: 3,114

    You can tell if they have enough/too much water when beads of water appear along the edges of the leaves.

    Tomatoes are a plant that can be grown hydroponically so I would think it is difficult to over-water, but easy to wash all the nutrients out of the grow-bag.

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